1. Field of the Invention
The present invention relates to a mobile vehicle (mobile object) such as a two-wheeled vehicle having a front wheel and a rear wheel.
2. Description of the Related Art
In a mobile vehicle, for example a motorcycle, having a front wheel and a rear wheel arranged spaced apart from each other in the longitudinal direction of the vehicle body, the front wheel usually serves as a steered wheel. In order to enhance the straight traveling property of the motorcycle, the steering axis of the front wheel (rotational axis of steering of the front wheel) is tilted backward (with a positive caster angle). Further, the axle of the front wheel is arranged on, or slightly behind, the steering axis.
As a result, a motorcycle of this type usually has a large positive trail. It should be noted that having a positive frail means that the point of intersection of the steering axis and the ground surface with which the wheels come into contact lies in front of the ground contact point of the steered wheel.
Further, as a motorcycle of this type, a motorcycle which is configured such that the rear wheel is passively steered by a reaction force that the rear wheel receives from the road surface when the motorcycle makes a turn is also known, as seen, for example, in Japanese Patent Application Laid-Open No. 04-224488.